Hrm. Any decent receiver will give specs for output power and THD at both 8 ohms and 4 ohms. While only you know the impedance of your speakers, you can safely stay away from anything that doesn't give specs for 4 ohm speaker connections as that's a dead giveaway that the amp's output circuits can't swing the amps needed to make up for the drop in impedance (cutting the impedance in half requires the output transistors to swing twice the amperage to maintain the same wattage).

Short take. If an amp has 8 ohm and 4 ohm specs, run it without fear on any 8 or 4 ohm speaker system. Anything else is hyper-priced audiophilia nervosa.

What he said. As long as the amp is stable at 4 Ohms you'll be fine with essentially any home speakers within reason. If you find one that's 2 Ohm stable (or lower)...that's a serious amplifier (generally) and will drive 4 Ohm+ loads all day long at maximum volume without even showing signs of stress.

ludi wrote:All Class AB amplifier designs produce a lot of waste heat, but some can produce more than others, and what you do with it once you've created it, matters. On the other hand, many users make matters much worse by cramming their gear into tight AV stacks, particularly alcove or cabinet configurations with poor ventilation.

This. Anyone who puts their components into an enclosed space without any active ventilation is just playing the amplifier death lottery.

That's another bit of good info: the lower the ohm rating of the amp, the better quality (or so should you expect). And it is best if the amp has equal or lower ohm rating than your speakers to handle them well.

My components are in an opened space, so I'm good there

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Vince, go check out avsforum.com. you can get all the info you need about so many different brands of AV receivers that you will be able to find one that fits your budget. ask yourself these few simple questions: do i need a 5.1 or 7.1 receiver, how many HDMI inputs do i need, do i want lesser or more watts per channel, and do i want to hook up my mp3 player or ipod to the receiver. For your under $500 range, Pioneer, Yamaha, and Onkyo are your best bets. Denon, Marantz, and Harmon Kardon are more high end and much more expensive. Also what you can do is go to your local Best Buy if live anywhere near one. They usually have some open box models fairly discounted because they are missing a remote or its just an older discontinued model. ive seen a Denon receiver for under $400 like that before.

vince wrote:That's another bit of good info: the lower the ohm rating of the amp, the better quality (or so should you expect). And it is best if the amp has equal or lower ohm rating than your speakers to handle them well.

Sort of. In most general-consumer gear, it's a good rule of thumb, but one major exception is when the front L/R channels include auxiliary speaker jacks for a second set of speakers, intended to provide stereo sound in an adjacent room. In that case, the front L/R channels typically drive both outputs in parallel and specify "8-Ohm only" because two 8-Ohm sets in parallel will present the equivalent of a 4-Ohm load. In that case the amplifier channels can drive a single set of 4-Ohm speakers if the auxiliary outputs are not used, but the labeling may not specify it.

Another thing designers may do is specify 4-Ohm compatibility, but not bother to over-rate the power supply for it. In many consumer configurations they will even rely upon power supply collapse to prevent the output devices from blowing up under heavy loading, in part because it's cheaper, but also because they cannot predict the oddball combinations of equipment that consumer will try to set up. Driving a low-impedance load actually tends to degrade the performance of any amplifier. The main reason 4-Ohm speakers were first invented was to handle the low power supply voltages available in 12V automotive applications, back before DC-to-DC converters became common in consumer electronics.

JohnC wrote:That was not the case for many Onkyo users, including me - I do not put my receivers into enclosure and I don't stack other similar equipment on top of them, so this point is irrelevant.

I agree: If this thread were exclusively about JohnC and faulty Onkyo receivers, then the point would be irrelevant.

I'm watching this thread with interest. I have an Onkyo 7.1 receiver that is 4 years old and is starting to go. It does not find the HDMI signal 80% of the time now (not managing the HDCP?)

The model I have is a 4 HDMI model and currently I have 5 HDMI devices I run (1 is direct to TV).

I The possible replacements I've looked at are all 6 HDMI or more 7.1 channel.

I have looked at many and all of them hover around $600. (In Canada so we pay about $100 more on this stuff then the USA)Onkyo TXNR515 Yamaha Aventage RX-A720Pioneer Elite VSX42Denon AVR-1913

All except the Onkyo have Apple Airplay built in, instead Onkyo has more inputs and 4K scaling for the same money.All hover around 90-100W per channel.All are 3D.Anyone have any opinion on any of them?

All except the Onkyo have Apple Airplay built in, instead Onkyo has more inputs and 4K scaling for the same money.

That Yamaha model also has 4K scaling, no? Although personally I believe it's way too early to consider the 4k upscaling/passthrough to be "useful feature"... Anyway, if you need more information about specific model you should try looking at http://www.avsforum.com/f/ they usually have dedicated threads related to specific models (or model ranges).

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Arvald wrote:I'm watching this thread with interest. I have an Onkyo 7.1 receiver that is 4 years old and is starting to go. It does not find the HDMI signal 80% of the time now (not managing the HDCP?)

Could just be a flaky connection in a cable or HDMI port, although a modern receiver mainboard is basically a purpose-built computer and can fail in many of the same ways as it ages.

ludi wrote:Sort of. In most general-consumer gear, it's a good rule of thumb, but one major exception is when the front L/R channels include auxiliary speaker jacks for a second set of speakers, intended to provide stereo sound in an adjacent room. In that case, the front L/R channels typically drive both outputs in parallel and specify "8-Ohm only" because two 8-Ohm sets in parallel will present the equivalent of a 4-Ohm load. In that case the amplifier channels can drive a single set of 4-Ohm speakers if the auxiliary outputs are not used, but the labeling may not specify it.

Another thing designers may do is specify 4-Ohm compatibility, but not bother to over-rate the power supply for it. In many consumer configurations they will even rely upon power supply collapse to prevent the output devices from blowing up under heavy loading, in part because it's cheaper, but also because they cannot predict the oddball combinations of equipment that consumer will try to set up. Driving a low-impedance load actually tends to degrade the performance of any amplifier. The main reason 4-Ohm speakers were first invented was to handle the low power supply voltages available in 12V automotive applications, back before DC-to-DC converters became common in consumer electronics.

Well you do have to watch for that kind of specification trickery. Generally I take all power ratings with a grain of salt unless they list all channels driven, some frequency, and a THD rating. I've yet to see a 2 Ohm stable home theater receiver that wasn't a good piece of equipment though.

EDIT: Yes, technically, dropping the impedance by half does increase the THD of the amplifier. I've never heard one that suffered from audible increases though.

JohnC wrote:Even the inexpensive models ($250) nowadays can handle HDMI switching in a proper way. B.t.w, why are you looking at this particular Marantz model? As far as I know there's no data that shows that it has a better reliability than other brand's receivers; in fact, it has its own well-known issue:https://www.google.com/search?q=Marantz ... =firefox-a

I only listed that because it's close in price to the one I'm actually looking at, the SR7002 which is in limited supply . If it sells out I'll probably just get a Denon.Either way it'd come from A4L

:edit:as for 4k scaling, I wouldn't let that be a deciding factor as a 4k tv would probably do a better job itself.

All except the Onkyo have Apple Airplay built in, instead Onkyo has more inputs and 4K scaling for the same money.

That Yamaha model also has 4K scaling, no? Although personally I believe it's way too early to consider the 4k upscaling/passthrough to be "useful feature"... Anyway, if you need more information about specific model you should try looking at http://www.avsforum.com/f/ they usually have dedicated threads related to specific models (or model ranges).

The promo material I had at the time did not list the 4K for Yamaha but I see that now.After much looking I'm set on the Yamaha and may buy today. I see many good postings for satified people for it.

As to my Onkyo failing, seems that the capacitors on the Onkyos HDMI board were not good enough for the heat generated by the unit and they dry out and die. There are instructions for a manual fix on avsforum so I may do the fix over the holidays and put this back into service on another TV.